The Simple Rating System (SRS) adjusts a team’s per-game run differential for strength of schedule. This SRS ranking uses data from all WBC matches since 2006, with extra weight applied to games in later rounds.

Source: Wikipedia

But the U.S. persevered through it all, and now they are WBC champions. And who knows — perhaps the win will even persuade more marquee players to represent America at future World Baseball Classics.